Shear Strength of Beryllium, Uranium, and Tungsten as a Function of Strain, Strain Rate, and Pressure

1971 ◽  
Vol 93 (2) ◽  
pp. 291-295 ◽  
Author(s):  
A. E. Abey ◽  
H. D. Stromberg
Keyword(s):  
Shear Strength ◽  
Strain Rate ◽  
Shear Strain ◽  
Strain Rates ◽  
Experimental Parameters ◽  
Derivatives Of ◽  
And Tungsten

The shear strengths of beryllium, uranium, and tungsten were measured at strain rates of 3.5 × 10−5, 3.6 × 10−3, and 3.7 × 10−1 sec−1. The measurements were taken under nearly hydrostatic pressures of 21, 44, and 63 × 108 N/m2. The shear strength versus shear strain curves are presented along with the pressure and in strain rate derivatives of the experimental parameters.

scholarly journals Erebus Glacier Tongue, Mcmurdo Sound, Antarctica

1974 ◽  
Vol 13 (67) ◽  
pp. 27-35 ◽  
Author(s):  
G. Holdsworth
Keyword(s):  
Shear Stress ◽  
Strain Rate ◽  
Shear Strain ◽  
Longitudinal Strain ◽  
Strain Rates ◽  
Shear Strain Rate ◽  
Mcmurdo Sound ◽  
Glacier Tongue ◽  
The Past ◽  
Image Position

Examination of the past and present behaviour of the Erebus Glacier tongue over the last 60 years indicates that a major calving from the tongue appears to be imminent. Calculations of the regime of the tongue indicate that bottom melt rates may exceed 1 m a−1. By successive mapping of the ice tongue between the years 1947 and 1970, longitudinal strain-rates were determined using the change in distance between a set of 15 teeth, which are a prominent marginal feature of the tongue. Assuming a flow law for ice of the form where τ is the effective shear stress and is the effective shear strain-rate, values of the exponent n = 3 and B = 1 × 108 N m−2 are determined. These are in fair agreement with published values.

The Mechanical Behavior of Synthetic Permafrost

1973 ◽  
Vol 13 (04) ◽  
pp. 211-220 ◽  
Author(s):  
T.K. Perkins ◽  
R.A. Ruedrich
Keyword(s):  
Shear Strength ◽  
Strain Rate ◽  
Mechanical Behavior ◽  
Stress Level ◽  
Flow Behavior ◽  
Petroleum Industry ◽  
Elastic Response ◽  
Strain Rates ◽  
Arctic Regions ◽  
Maximum Shear Strength

Abstract Discoveries of oil in Arctic regions have led to several engineering problems that are relatively new to the petroleum industry. An understanding of some of the new problems associated with construction of surface facilities as well as with the drilling and completion of wells requires an understanding of the mechanical properties of permafrost. permafrost. Synthetic permafrost samples have been prepared from quartz sand as well as from natural soils taken from Prudhoe Bay permafrost cores recovered from depths as great as 1,753 It. All samples have been recompacted and frozen under a condition of zero confining stress. Samples prepared in this way should exhibit behavior similar to that of shallow permafrost. Samples have been tested in uniaxial permafrost. Samples have been tested in uniaxial compression at constant strain rates as well as with constant axial stress. At constant temperature and low strain rates, the log of the maximum shear strength will plot as a straight line vs the log of the strain rate. For sand-ice samples at high strain rate, another mode of failure was evident that led to a maximum shear strength independent of strain rate. Under triaxial conditions, the maximum shear strength of sand-ice samples was generally increased with increasing stress level. In uniaxial tension, the tensile strength of sand-ice samples was found to be a function of temperature and strain rate. Elastic response of these samples was obscured by the more dominant flow behavior at low strain rates. Only at clearly high strain rates was an elastic response clearly discernible. Young's modulus measured after 10 to 15 percent plastic strain increases with increasing stress level. Introduction Within the last few years significant oil discoveries have been made in Arctic regions. There is much speculation that additional oil will be found in regions that are characterized by quite low ambient and soil temperatures. The drilling of wells and production of oil under these environmental conditions poses new problems not traditionally faced by the petroleum industry, but which presumably will be of increasing concern within the presumably will be of increasing concern within the next few years. One new engineering challenge is that of dealing with permafrost, soil which has been continuously frozen for a number of years. Already at Prudhoe Bay a number of wells have been drilled through about 2,000 ft of permafrost. As an example of permafrost influence, measurements have shown that, when thawed permafrost around a well refreezes, significant pressures can be generated. In order to understand this phenomenon, it will be necessary to understand the mechanical behavior of permafrost. In addition, surface facilities have been permafrost. In addition, surface facilities have been constructed where there is a thin, active region (which thaws during summer months) underlain by permafrost. An understanding of permafrost permafrost. An understanding of permafrost mechanical behavior will aid in the design of foundations for surface facilities. There are a number of variables that can influence the mechanical behavior of frozen soils such as minerology, percent of ice saturation, presence of excess ice, salt content, etc. In this paper we will describe a laboratory study of relatively fine-grained granular materials with pore spaces saturated with ice. The results presented here may not be applicable to frozen clays or gravels, where pore spaces are undersaturated or where a large amount of excess ice is present. Since permafrost is composed of ice and soil, its behavior will naturally reflect that of its constituents. The rate of yield or flow of ice is known to be a function of temperature, shear stress and strain, but is independent of hydrostatic pressure level. Soil, on the other hand, exhibits pressure level. Soil, on the other hand, exhibits yield behavior that is independent of temperature over the small range of permafrost temperatures of interest. For sandy soil, yield behavior is relatively independent of strain rate, but is significantly influenced by strain and stress level. Under stress, a dominant characteristic of shallow permafrost is that of yield or flow. Its rate of flow will be a function of all the variables mentioned above. Over-all deformation results from a combination of elastic and flow behavior. SPEJ P. 211

scholarly journals Dynamic Shear Characteristic and Fracture Feature of Inconel 690 Alloy under Different High Strain Rates and Temperatures

2013 ◽  
Vol 2013 ◽  
pp. 1-5
Author(s):  
Tao-Hsing Chen ◽  
Chih-Kai Tsai ◽  
Te-Hua Fang
Keyword(s):  
Strain Rate ◽  
Shear Strain ◽  
High Strain ◽  
Rate Sensitivity ◽  
Shear Behaviour ◽  
Strain Rates ◽  
Dynamic Shear ◽  
Fracture Feature ◽  
Strain And Strain Rate ◽  
Inconel 690

The high strain shear rate behaviour of Inconel 690 alloy was investigated by using the split Hopkinson torsional bar. The shear strain rates were tested at 900 s−1, 1900 s−1, and 2600 s−1and at temperatures of −100°C, 25°C, and 300°C, respectively. It was found that the dynamic shear behaviour of Inconel 690 alloy was sensitive to strain rate and temperature. The fracture shear strain increased with increasing strain rate and temperature. In addition, the strain rate sensitivity was increased with increasing strain and strain rate but decreased with increasing temperature. Finally, the fracture surfaces were found to contain dimple-like features, and the dimple density increased with increasing strain rate and temperature.

scholarly journals Shearing Rate Effects on Research Centre for Soft Soils (Recess) Clay Using Cone Penetration Test (CPT)

2015 ◽  
Vol 773-774 ◽  
pp. 1555-1559
Author(s):  
Azranasmarazizi Ayob ◽  
Nor Azizi Yusoff ◽  
I. Bakar ◽  
Nur Abidah Azhar ◽  
Ameer Nazrin Abd Aziz
Keyword(s):  
Shear Strength ◽  
Strain Rate ◽  
Shear Strain ◽  
Penetration Rate ◽  
Cone Penetration Test ◽  
Shear Strain Rate ◽  
Penetration Test ◽  
Cone Penetration ◽  
Rate Effects ◽  
Cpt Test

A wide range of industrial applications, on land and offshore, require the solution of time domain problems and an associated understanding of rate effects in clay soils. In recent decades many researchers have examined the correlation between shear strength of soils and variation of shear strain rate and it is generally accepted that the strength increases by 1-5% for each order of magnitude increase in shear strain rate. This paper discusses the effects of penetration rate on the penetration resistance (qc) by using cone penetration test (CPT) test setup. The research had been conducted at RECESS and cone penetration test were used in three selected range of rate which were 0.5 cm/s, 1cm/s and 5cm/s. In addition, Mackintosh probe testhad been considered as comparison with CPT test for the unconfined compressive strength. The result shows different penetration rate influenced the soil shear strength. For the slowest rate (0.5 cm/s), the shear strength was approximately 0.15% less compared to the standard rate (2 cm/s). However, for the highest rate (5 cm/s), the shear strength was 0.22% more than the reference rate (0.5 cm/s). In conclusion, it is suggested that the RECESS clay soil influenced by the rate effect and in agreement with previous research findings.

scholarly journals The effect of loading rate on the in-plane shear strength of tri-axial braided composites

2021 ◽  
pp. 002199832110476
Author(s):  
Michael May ◽  
Sebastian Kilchert
Keyword(s):  
Shear Strength ◽  
Composite Materials ◽  
Strain Rate ◽  
Shear Test ◽  
Loading Rate ◽  
Strain Rates ◽  
Braided Composites ◽  
Plane Shear ◽  
Braided Composite

The in-plane shear strength of tri-axial braided composite materials was measured for three different braid angles (30°, 45°, and 60°) and two strain rates (0.001 s−1; 3 s−1) using the three-rail shear test. The in-plane shear strength was found to be sensitive to both—the braid angle and the strain rate. An increase of braid angle resulted in a reduction of shear strength, whilst an increase of loading rate resulted in an increase of shear strength of 8%–17%, depending on the braid angle.

Strain Rate Effect on Out of Plane Shear Strength of Fiber Composites

2007 ◽  
Vol 345-346 ◽  
pp. 725-728
Author(s):  
Jia Lin Tsai ◽  
Jui Ching Kuo
Keyword(s):  
Shear Strength ◽  
Strain Rate ◽  
Shear Strain ◽  
Fiber Composites ◽  
Strain Rate Effect ◽  
Rate Effect ◽  
Strength Analysis ◽  
Shear Strain Rate ◽  
Plane Shear ◽  
Out Of Plane

This research aims to investigate strain rate effect on the out of plane shear strength of unidirectional fiber composites. Both glass/epoxy and graphite/epoxy composites were considered in this study. To demonstrate strain rate effect, composite brick specimens were fabricated and tested to failure in the transverse direction at strain ranges from 10-4/s to 700/s. Experimental observations reveal that the main failure mechanism of the specimens is the out of plane shear failure taking place on the plane oriented around 30 to 35 degree to the loading direction. The corresponding out-of-plane shear strength was obtained from the uniaxial failure stress through Mohr-Coulomb strength analysis. In addition, the associated shear strain rate on the failure plane was calculated through the coordinate transformation law. Results show that the out-plane shear strength increases with the increment of the shear train rates. A semi-logarithmic function expressed in terms of the normalized shear strain rate was employed to describe the rate dependence of the out-plane shear strength.

scholarly journals A 3 Year Record of Seasonal Variations in Surface Velocity, StorglaciÄren, Sweden

1989 ◽  
Vol 35 (120) ◽  
pp. 235-247 ◽  
Author(s):  
Roger LeB. Hooke ◽  
Peter Calla ◽  
Per Holmlund ◽  
Mats Nilsson ◽  
Arjen Stroeven
Keyword(s):  
Strain Rate ◽  
Shear Strain ◽  
Seasonal Variations ◽  
High Velocity ◽  
Water Pressure ◽  
Force Balance ◽  
Surface Velocity ◽  
Time Interval ◽  
Strain Rates ◽  
Lateral Shear

Abstract Between 3 June 1982 and 8 July 1985, a stake net consisting of up to 32 stakes covering the greater part of Storglaciären was surveyed 70 times, yielding roughly 2000 separate determinations of vertical and horizontal velocity. The time interval between surveys averaged about 1 week during the summer and 2 months during the winter. Horizontal velocities were normally highest during periods of high daily temperature or heavy rain early in the melt season. Comparable or sometimes higher temperatures or rainfalls later in the season usually had less effect, though minor velocity peaks were often present in August and early September. During periods for which bore-hole water-level measurements are available, velocity peaks generally coincided with periods of high basal water pressure, but not all periods of high water pressure resulted in velocity peaks. Despite increasing basal water pressures, velocity decreased gradually during the winter. Vertical velocities also vary seasonally. Beneath the upper part of the ablation area the glacier bed is overdeepened. Vertical velocities here are ˜3 mm/d higher during the summer. Down-glacier from the overdeepening, vertical velocities are ˜1 mm/d lower during the summer. These and other characteristics of the vertical velocity pattern are best explained by appealing to: (1) a decrease in strain-rate with depth, and (2) seasonal variations in this depth-dependence. Five periods of high velocity lasting from 3 to 11d were studied in detail. In an area where the bed is overdeepened, force-balance calculations suggest that basal drag decreased between 16 and 40% during these high-velocity events. This resulted in a decrease in compressive strain-rate at the up-glacier end of the overdeepening, an increase at the down-glacier end, and a slight increase in lateral shear strain-rates. Down-glacier from the overdeepening, basal drag increased during two events owing to an increased push from up-glacier and pull from down-glacier. Lateral shear strain-rates increased sharply here.

scholarly journals Study on the Impact of Strain Rate and Loading Speed on Geogrid-Reinforced Soil

2017 ◽  
Vol 10 (2) ◽  
pp. 238
Author(s):  
Mohammadehsan Zarringol ◽  
Mohammadreza Zarringol
Keyword(s):  
Shear Strength ◽  
Strain Rate ◽  
Contact Area ◽  
Reinforced Soil ◽  
Vertical Stress ◽  
Coarse Grained ◽  
Strain Rates ◽  
The Past ◽  
The Impact ◽  
Coarse Grained Soil

During the past decades, reinforced soil has normally been constructed by coarse grained soil. Recently, low quality and locally accessible materials have been successfully used in reinforced soil due to economic observations. Loading speed is one of the effective factors in soil-geosynthetic interaction. In order to determine the impact of this factor, we carried out a pullout test on the samples with dimensions of 30×30×17 cm under four strain rates of 0.75, 1.25, 1.75 and 2.25 mm/min and three vertical stress rates of 20, 50 and 80 KN/m2. The results of this study indicated that the mobilization of geosynthetic strength in contact area depends on the amount of vertical stress. The increased vertical stress results in the increased shear strength in clay-geogrid contact area. Furthermore, the increased strain rate results in the reduced shear strength.

Strain Rate Dependent Constitutive Model of Multiaxial Ratchetting of 63Sn–37Pb Solder

2006 ◽  
Vol 129 (3) ◽  
pp. 278-286 ◽  
Author(s):  
Gang Chen ◽  
Xu Chen ◽  
Kwang Soo Kim ◽  
Mohammad Abdel-Karim ◽  
Masao Sakane
Keyword(s):  
Constitutive Model ◽  
Strain Rate ◽  
Shear Strain ◽  
Kinematic Hardening ◽  
Axial Stress ◽  
Strain Range ◽  
Strain Rates ◽  
Shear Strain Rate ◽  
Viscous Term ◽  
Ratcheting Strain

A series of multiaxial ratcheting tests were conducted on 63Sn–37Pb solder. A unified viscoplastic constitutive model was developed on the basis of the Ohno–Wang kinematic hardening model, and the rate dependence of the material was taken into consideration by introducing a viscous term. The stress-strain hysteresis loop of 63Sn–37Pb under different strain rates can be simulated reasonably well by the model. However, since the axial ratcheting strain rate of 63Sn–37Pb solder is strongly dependent on the applied shear strain rates in axial/torsional ratcheting, the original constitutive model fails to describe the effect of shear strain rate on the ratcheting strain. To improve the rate sensitivity of the model, the material parameter μi was correlated to the strain rate. Comparisons of the experimental and simulated results verify that the modified constitutive model is able to predict the complicated deformation of 63Sn–37Pb. The effects of axial stress, shear strain range, loading history, and strain rate on ratcheting behavior can be reflected fairly well.

scholarly journals Deformation rates in combined compression and shear for ice which is initially isotropic and after the development of strong anisotropy

1996 ◽  
Vol 23 ◽  
pp. 247-252 ◽  
Author(s):  
Li Jun ◽  
T.H Jacka ◽  
W.F. Budd
Keyword(s):  
Shear Stress ◽  
Steady State ◽  
Stress State ◽  
Strain Rate ◽  
Shear Strain ◽  
Uniaxial Compression ◽  
Simple Shear ◽  
Strain Rates ◽  
Shear Strain Rate ◽  
State Dependent

Laboratory-prepared fine-grained, initially isotropic polycrystalline ice samples were deformed under conditions of simple shear with simultaneous uniaxial compression at a constant temperature of −2.0°C. The aim was to investigate the effects of stress configuration on the flow rate of initially isotropic ice and on ice with subsequent stress and strain-induced anisotropy. Experiments were carried out for various combinations of shear and compression with shear stress ranging from 0 to 0.49 MPa and compressive stress ranging from 0 to 0.98 MPa, but such that for every experiment the octahedral shear stress was 0.4 MPa.The strain curves resulting from the experiments clearly exhibit minimum strain rates while the ice is still isotropic, and steady-state tertiary strain rates along with the development of steady-state anisotropic fabric patterns. With constant octahedral stress (root-mean-square of the principal stress deviators), the minimum octahedral shear-strain rate has no dependence on stress configuration. This result supports the hypothesis that the flow of isotropic ice is dependent only on the second invariant of the stress tensor. This fundamental assumption has been used to provide a general description of ice-flow behaviour independent of the stress configuration (e.g. Nye, 1953; Glen, 1958; Budd, 1969).For the tertiary flow of anisotropic ice, the octahedral strain rate is stress-state dependent as a consequence of the developed crystal-orientation fabric, which is also stress-state dependent, and which develops with strain and rotation. The present tests indicate that the enhancement factor for steady-state tertiary octahedral shear-strain rate depends on the shear or compression fraction and varies from about 10 for simple shear (with zero compression) to about 3 for uniaxial compression (with zero shear).

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